Annual report on EL 5319 Ringwood South.

Abstract

F17 Stockwork Prospect A prominent ridge of siltstones and wackes of the Gerowie Tuff - Mt Bonnie Formation transition to the north-west of the Mt Paqualin hosts an extensive quartz-limonite-(haematite) stockwork. The ridge lies on the western limb of the F17 Anticline. The central portion of the ridge was subjected to close spaced (2 x 10m x -80#, 50m line spacing's) soil sampling in 1986 and two diamond drill holes (FSDD29 and 30) were drilled as a test of the strong gold and arsenic anomaly defined by the soils. The best interception gained was 4.8m 1.39 g/t in FSDD29. Work in 1987 extended the soil sampling survey north to 13900N and south to 9800N (F17 grid). 854 2 x 1Dm x -80# soil samples were collected. Grid mapping and rock-chip sampling covered the soil anomalous portion of the ridge delineated in 1986. The mapping has been complied at 1:5000. A marked contrast in tenor of soil gold anomaly was noted between the northern segment of the F17 ridge (sampled in 1987, using 30 gram ppb analysis) and the central segment of the ridge (sampled in 1986 using 5 gram ppb analysis). The central segment contained numerous values of >100 ppb gold, whilst the northern segment 'suddenly' displayed most values <50ppb. Suspecting analytical error (ie. Anomaly enhancement by using the 5 gram method), two 'highly anomalous' grid lines of the 1966 survey were re-sampled late in 1987 and subjected to both 5 gram and 30 gram analytical methods. It is apparent from geometric means that the data is little affected by the change in analytical methods. However, the 5gm Au analyses has a greater coefficient of variation than the 30gm Au analyses due to the greater sampling error in using only a 5gm aliquot of the sample. There is not much change between the geometric means between the 1986 Au 5gm analyses and the 19S7 Au analyses (both methods) given that the samples are offset by l0m systematically. As a result the two sets of data for P17 grid should be comparable. The comparison of Au 5gm analyses with Au 30gm analyses for the 1987 data has been done by calculating both analytical variance and precision. The analytical variance is quite high (0.047) and the precision is quite poor for these samples (19.3%). Again this is attributed to the greater sampling error in a 5gm aliquot compared with a 30gm aliquot. Quest Far South Prospect - This prospect lies on the western limb of the Quest 155 Anticline, over modestly quartz-veined, but otherwise unremarkable Gerowie Tuff ridges south of Howley Creek and Quest 155 itself. Soil sampling was undertaken in 1987 (2 x 20m x -80#m lines 100m apart, with 50m infills later) on the strength of several +1 g/t rock-chip assays gained whilst mapping in 1985. A total of 277 soil samples were taken.The anomaly is strongest between 10850N and 1105014 where a zone of +l00ppb Au emerges from under black soil to the west. Ground magnetics coverage for Quest 155 finishes at 11000N, and the profiles are essentially featureless on that line. The southern most drilling around Quest 155 was targeted on the 'Quest South' vein on 11500 N. Here the top of the gabbro has been interpreted to be 40 m below surface. However a vertical hole on 11600N intersected the gabbro at 30m depth. The intervening 3-400 m of black-soil covered ground adjacent to Howley Creek is extremely interesting in that the major fault of the 10900 area of Mt Paqualin should strike right through here. It may at least be speculated that the gold anomalous quartz veins on the western limb of the Quest 155 anticline at Quest Far South maybe the surface expression of a thrust up the gabbro-sediment contact, with the gobbro quite close to the surface. The lack of magnetic signature precludes us from getting too excited about this, however. The Quest Far South environment is interesting from another perspective also. It lies at the southern end (as far as our ground holding is concerned) of a prominent air-photo lineament which forms a drainage low over or adjacent to the F16-F16 West prospects, Bona Rush alluvials, Quest 150 bullseye aeromagnetic anomaly and Quest Far South. The significance of this structure is not clear at this stage, but prospects all along it are due for testing in the coming field season. Quest North-East Mag Prospect - As the name implies, this area lies to the north-east of Quest 155 and is a well defined aero-magnetic anomaly. The peak of the anomaly lies over alluvial creek deposits. Six and a half lines of ground magnetics were read over the anomaly late in 1987 (l0m stations, 3m pole) as follows:- 12500 N 12700 E - 14440 E, 12600 N 12700 E - 14500 E, 12700 N 12700 C - 14500 C, 12800 N 12700 C - 14690 C, 12900 N 12700 C - 14700 C, 13000 N 13300 C - 14700 C, 13100 N 12700 C - 14700 E, 13300 N 12700 C - 13300 C, Total: 13.24 line km field data sheets for this programme are presented in Apendix 4. The survey satisfactorily located the peak of the aeromagnetic anomaly on the ground. The 1988 work. programme will endeavor to work this prospect up to drillable status. Howley Prospect - The Howley prospect lies on the axis of the Rowley Anticline between Bons Rush and Howley Creeks and is a zone of intense ferruginous quartz brecciation within the Koolpin Formation. A Grace costean through the area yielded several metres of anomalous rockchips. The area was covered by soil sampling this year; 2 x 10m x -80#, on 6 lines 100m apart, for 147 samples. A strong gold response was recorded over the ferruqinous breccia - generally 30 ppb with a peak of 1030 ppb. Stronq arsenic anomalies compliment the gold data. The soil anomaly is open to the south (beyond 13300 N). The forward programme far this area is discussed In. section 4 of this report. The Southern Howley Anticline - This heading covers targets along the flanks of the Howley Anticline and at or to the south of Mt. Paqualin. The largely concordant F17 gabbro sill is emplaced 10-20m from the base of the gerowie Tuff although occasionally it lies between the gerowie Tuff and the underlying koolpin formation. With the disappointment of the 1986 costeaning of soil anomalies on sub-cropping F17 gabbro we have been left with 3 primary targets - all F17 gabbro on the western limb of the Howley Anticline, and all concealed either beneath Chinese-worked alluvial deposits or Mountt Paqualin scree. Each prospect was found in 1985 with traverse RAB drilling (holes 20m apart on l00m spaced lines, penetrating a minimum of 5 metres into gabbro bedrock) and each prospect was drilled in 1986 with RC/percussion. It needs to be pointed out that we have documented a problem with coarse gold in sulphidic samples from, within the Paqualin targets. That is, 'repeat' assays have been quite different to the original assays. This is being overcome, by mixermill assays; i.e. pulverisation for 20-30 minutes of all available crushed reject (perhaps up to 3kg, rather than the standard aliquot of 100-200 grams) followed by duplicate analyses.